Support belts are used in conveying devices, for example elevator installations, escalators, moving walkways, hoists or cranes. The support belts generally comprise several strands which consist of steel wires and which absorb the tensile forces to be taken up by the support belt. The strands are usually enclosed by a casing of synthetic material. The casing protects the strands from, for example, mechanical wear, since the support belts are frequently guided over deflecting points, particularly rollers.
The support belts within conveying equipment are a safety-critical component, since failure or breakage thereof can lead to dropping down of the cargo. This can lead to significant damage to property and harm to persons. For this reason, use is made in conveying equipment of checking units which check, in particular, the mechanical state of the strands. Damage to the strands absorbing the forces shall thereby be capable of early recognition in order that the support belt in the case of damage can be exchanged so as to prevent failure of the conveying equipment.
The strands are surrounded by the electrically insulating casing of synthetic material. In order to carry out a check of the state of the strands, contacting of the strands by a contact element is usually required. In general, with the help of the contact a current is conducted through the strands and serves the purpose of a check current determining the state of the strands. Apart from that, other methods of checking which do not operate with electrical current, for example ultrasonic, also come into consideration.
DE 39 34 654 A1 shows a support belt according to the above-described category. The ends of the strands are in that case conductively connected in pairs with a bridge member so that the strands of the support belt are electrically connected in series. The strands of the support belt are connected with a voltage source by way of an ammeter so that the state of the strands can be checked by means of the check current conducted through all strands on the basis of the electrical connection in series.
DE 2 330 038 shows a system for contacting a flat cable. In the illustrated flat cable several strands are arranged adjacent to one another within a plane and surrounded by a casing. For electrical contacting of the strands the flat cable is clamped in place by an upper and a lower clamping member. Recesses through which insertion prongs formed at a contact carrier can be guided are arranged at the lower clamping member. The insertion prongs thereby pierce the casing of the flat cable and thus come into contact with the strands. The contacting of the strands by means of the insertion prongs is thereby carried out perpendicularly to a longitudinal axis of the strands. It is necessary in this contact-making that the insertion prongs pierce the casing of the support belt, which is disadvantageous. The piercing of the casing by the insertion prongs can, however, have the consequence that the insertion prongs during piercing of the cable depart from the intended insertion direction and as a consequence contact with the strands cannot be made. The insertion prongs can thus possibly also contact other, unintended strands or even fail to contact a strand during piercing of the casing.
WO 2005/094249 A2 and WO 20061127059 A2 show a system for contact-making with a support belt in which the contact elements initially pierce the casing of the support belt perpendicularly to a longitudinal axis of the strand and then penetrate the strands. It is disadvantageous in that case that due to the required process of piercing through the casing the contact elements can miss the strands.
WO 2005/095251 A1 shows a system for contact-making with a support belt, in which the strands are contacted by a contact element perpendicularly to a longitudinal axis of the strands. In that case the contact elements pierce the casing of the support belt. The connecting device for contacting and fixing the support belt is then also used as a load securing element.